The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 09, 2006
Filed:
Jul. 15, 2003
James Jeffery Jacob, Watsonville, CA (US);
Andrew John Merriam, San Francisco, CA (US);
James Jeffery Jacob, Watsonville, CA (US);
Andrew John Merriam, San Francisco, CA (US);
ACTINIX, Scotts Valley, CA (US);
Abstract
We disclose several instrument architectures for the measurement of arbitrary phase retardation on advanced lithography photomasks. These architectures combine traditional interferometric techniques with high-magnification UV microscopy. Features are interrogated using a multitude of phase probes, formed by a imaging a number of variable apertures back-illuminated by phase-coherent beams, onto the surface of the photomask with a given demagnification. The size, spacing, and orientation of the phase probes may be adjusted to suit photomask feature geometries. Means are provided to vary the relative optical phase between the phase probes. These phase probes both reflect from and transmit through the photomask; the stationary, non-localized interference fringes, formed in the regions of phase probe electric field overlap, contain information on the optical path difference between the two probes. The spatial resolution of these measurements is limited only by the resolution limit of the UV microscope, which may significantly exceed the capability of existing tools.